Detection system for railway cars



25, 1964 A. v. DASBURG ETAL 3,145,953

DETECTION SYSTEM FOR RAILWAY CARS 3 Sheets-Sheet 1 Filed May 1, 1961 INVENTORS. A.V. DASBURG AND E.J. SEXTON JR.

THEIR ATTORNEY g- 25, 1964 A. v. DASBURG ETAL 3,145,958

DETECTION SYSTEM FOR RAILWAY CARS 3 Sheets-Sheet 2 Filed May 1, 1961 INVENTORS. A.V. DASBURG AND i E.J. SEXTON JR.

mm U THEIR ATTORNEY Aug. 25, 1954 A. v. DASBURG ETAL 3,145,958

DETECTION SYSTEM FOR RAILWAY CARS 5 Sheets-Sheet 3 Filed May 1, 1961 5,0 SWITCH CONTROL CIRCUITRY Ec:j AND RELAYS DUCER s APPARATUS TRAN INVENTORS. A.V.DASBURG AND E. J. SEXTON JR. BY

THEIR ATTORNEY United States Patent 3,145,958 DETECTION SYSTEM FOR RAILWAY CARS Alfred V. Dasburg and Edward J. Sexton, Jr., Rochester,

N.Y., assignors to General Signal Corporation, a corporation of New York Filed May 1, 1961, Ser. No. 106,727 2 Claims. (Cl. 246-160) The present invention relates to the detection of railway cars, and more particularly to the reliable detection of railway cars traversing track switches in a classification yard.

In railroad classification yards, individual cars or cuts of cars are selectively routed to predetermined classification tracks by means of a plurality of track switches. Each of the track switches, which are operated by power switch machines that are remotely controlled from a central office, are provided with means for preventing their operation while being traversed by a railway car that is rolling towards its intended classification track. The most reliable method of preventing the operation of a switch beneath a car is to control the application of power to the switch machine through a contact of a track relay which operates on the closed circuit or fail-safe principle. Thus, a detector track section is provided for each switch, which is electrically isolated by spaced insulated joints that are located in advance of the switch points and the frog portion of the switch to define the ends of the detector track section. Each detector track section is provided with a track circuit that includes the rails of the track section and a normally energized track relay. The occupancy of the track section by the axle assembly of the car shunts this track circuit to deenergize the track relay. With this reliable and failsafe means of detection, not only is the operation of the switch machine eifectively prevented, but also this track relay may be used to transfer storage and route descriptions for the individual cars or cuts of cars in succession as they shunt and vacate respective detector track sections.

To permit the relatively close spacing of the individual cars or cuts of cars as they travel from the hump and through the switches, thus providing maximum use of the yard and etficiency of operation, these detector track sections are made as short as possible. The maximum length of each detector track section is determined by the maximum distance between the front and rear inner axle assemblies of the freight cars normally in use, to insure that the detector track section would not be spanned by a car traversing a switch. This length is in the neighborhood of 38 feet for the average car.

However, railroad cars which have a longer distance than 38 feet between their front and rear inner axle assemblies, such as 54, 65, or even 70 feet, for example, are now in popular use. This presents a problem in that the longer cars span the detector track sections as they travel over the switches through the yard, which permits the track switch to be thrown beneath these long cars during the time of spanning. Also, automatic classification systems cannot be used for automatically routing these long cars to their intended destination because the systems are so constituted that the intermediate operation of the track relay during the spanning is tantamount to the detection of more than one car or cut of cars.

Heretofore, when these long cars were to be classified 3,145,958 Patented Aug. 25, 1964 it was necessary to select the position of the switch manually, independently of the automatic control apparatus. This was time consuming and reduced the efficiency and handling capacity of the yard. Moreover, even with separately classifying these long cars the danger of the switch being inadvertently thrown beneath a car was not remedied.

The purpose of the present invention is to provide a system which operates on the closed circuit or fail-safe principle, and yet is effective to reliably detect those cars which span the detector track sections, as well as those which do not span the track sections, without physically lengthening each of the detector track sections now installed, and without decreasing the efiiciency of operation of a classification yard.

In View of the above, one of the objects of the present invention is to provide a system which incorporates the advantages of the closed track circuit for detecting railway cars which will span the detector track section when traversing a track switch.

Another object of this invention is to provide a system of the character described which does not require any greater spacing between the individual cars or cuts of cars thereby to decrease the efficiency of the classification yard.

Another object of this invention is to provide a system of the character described which further improves the reliability of an already fail-safe track circuit of a detector track section.

A further object of this invention is to provide a system which effectively and reliably lengthens an existing detector track section by an amount which corresponds to the distance between the inner axle assemblies of each car to detect continually those cars which span the detector track section when traversing a track switch.

A still further object of this invention is to provide a system whereby the operation of the ultrasonic detecting apparatus used in conjunction with the present invention is checked for its reliability of operation each time a car traverses a track switch.

Other objects of this invention will become apparent from the specification, the drawings, and the appended claims.

In the drawings:

FIG. 1 is a fragmentary side elevation of a detector track section spanned by the axle assemblies of a railway car showing the detector apparatus and its location according to this embodiment of the invention;

FIG. 2 is a fragmentary plan view of a track switch showing the position of the detecting portion of the system in a typical installation according to the present invention;

FIG. 3 is a block diagram showing the apparatus used in connection with the ultrasonic detector of the present invention;

FIG. 4 is a diagrammatic view partly in block form showing the apparatus and circuitry according to the one embodiment of the invention;

FIG. 5 is a diagrammatic view partly in block form showing the apparatus and circuitry according to a second embodiment of the invention; and

FIG. 6 is a diagrammatic view partly in block form showing the apparatus and circuitry according to a third embodiment of the invention.

Referring to the drawings, and particularly to FIGS.

1 and 2, a track switch generally referred to at is included in the detector track section comprised of rails 12 and 13. The detector track section, which is electrically isolated from the rest of the track is defined by insulated joints 16 which are located slightly in advance of switch points 18 and is defined at the other end by insulated joints 20 which are located in front of frog portion 22 of the track switch 10. The insulated joints 16 are located far enough in advance of the switch points 18 so that a switch movement that is commenced just prior to the occupancy of the detector track section by a car will be completed before the wheels engage the switch points 18. The various intermediate insulated joints and cross bond to render the track circuit of the detector track section operative are well known in the art and have been omitted for the sake of clarity.

When the distance between the insulated joints 16 and 20 or in other words, the length of the detector track section is in the neighborhood of 38 feet, for example, a long freight car, such as is referred to at 25 in FIG. 1 spans the detector track section when it is directly over or traversing the track switch 10. While spanning the detector track section, rear axle assembly 26 of the car 25 is located in advance of the insulated joints 16 and front axle assembly 28 of the car 25 are located slightly to the rear of the insulated joints 20. Positioned between the rails 12 and 13 adjacent the frog portion 22 of the track switch and mounted on a tie 32 which is located slightly in advance of the frog portion 22 is an ultrasonic detector head 30.

The ultrasonic detector head 30 is a single unit, having a frequency transmitting and receiving portion which is preferably facing downwardly, and is attached to the tie 32 by a bracket 34. A casing 36 is connected to the head 30 and serves to reflect the ultrasonic frequencies upwardly as represented by the dotted lines at 38 (FIG. 1). The casing 36 has an opening which is covered by a screen 37 to prevent foreign matter, such as dirt for example, from entering the casing 30 and interfering with the operation of the ultrasonic detector. With the ultrasonic detector 30 and its casing 36 located between the rails 12 and 13 in front of the frog portion of the switch, a freight car passing over the switch will be reliably detected as hereinafter described whether the switch is in a normal or reverse position. The detector head 30 and its casing 36 is preferably located below the levels of the rails 12 and 13 so that it cannot be injured or damaged by any dragging equipment or other apparatus which may extend from the freight car passing over the switch 10.

The unitary ultrasonic detector head 30, which serves to transmit and receive the ultrasonic waves is operatively connected in a well known manner to transducing apparatus generally referred to at 41, which is comprised of a conventional bybrid transformer network 42 (FIG. 3) that is so connected to a pulse generator 44 to cause the head 30 to transmit the ultrasonic waves therefrom. A reflected pulse reception circuit 46 detects the ultrasonic waves which are transmitted when they bounce or echo back from the surface of a passing freight car. The reception of these reflected waves serves to cause a conventional gated detection circuit 48 to deenergize a detector relay D. When no ultrasonic frequency is being received by the ultrasonic detecting head 30, which would be the case when no portion of a freight car is located above the casing 36, the detector relay is held energized through the gated detection circuitry 48. When the refiected pulse reception circuitry and apparatus 46 de tects the reception of ultrasonic waves which are caused by the passage of a car, the relay D is deenergized. An ultrasonic detecting system, such as that described in the copending application 845,810 filed October 12, 1959, and assigned to the common assignee, which has resulted in Patent No. 3,030,608, granted April 17, 1962, may be used with this equipment of the invention, for example. This ultrasonic detecting head 30 and its casing 36 when positioned according to the present invention detects each car or cut of cars beginning with the front end and ending with the rear end of the last car in a cut. With the detector so positioned, detection occurs regardless of the type of car traveling over the switch, and will not detect persons walking alongside the track nor other cars on adjacent tracks or objects outside the track structure.

The switch It) is power operated by a conventional switch machine SM which is diagrammatically illustrated in FIGS. 4, 5 and 6. The switch machine SM is operated in a conventional manner by an electric motor which is controlled to operate the switch machine to either its normal or reverse position by a well known relay switch control relay network 50. A source of energy 52 is connected in a well known manner across the rails 12 and 13 of the track section between the insulated joints 16 and 20 for providing the necessary energy to operate a track relay T.

In the embodiment of the invention illustrated in FIG. 4, the winding of the track relay T is connected at one side to the track rail 13 at 53, and is connected at its other side through a front contact 54 of the detector relay D to the track rail 12 at 55. The relay T is normally energized when no car is occupying the detector track section or influencing the detector 30. When a car, through its wheel and axle assembly, engages the track rails 12 and 13 to shunt the track circuit, which is com prised of the track relay T, the track rails 12 and 13 and the source of energy 52, the relay T drops away in a manner well known in the art, which causes its front contact 56 to open. The opening of the front contact 56 removes energy from the switch control circuitry 50 thus preventing the power operation of the switch machine SM. When the car passes over the screen 37 of the casing 36, the relay D is deenergized which opens the energizing circuit of the track relay T. When a car, such as 25, spans the track section between the insulated joints 16 and 20, but the wheel and axle assemblies are no longer shunting the detector track section, the track relay T is prevented from becoming reenergized because of the open front contact 54 of the detector relay D. When, after spanning the track section, the car again shunts the track circuit, the relay T is further prevented from becoming reenergized if there should be an improper shunting because of the open front contact 54 of the relay D. Because of the position of the detector 30, a momentary loss of shunt would still prevent the track relay from becoming reenergized. When the car passes beyond the casing 36 of the detector 30, the track relay is controlled solely by its track circuit, and when the rear of the car passes beyond the insulated joints 20, the track relay again picks up to close its front contact 56 so that the switch may be operated by the switch machine SM.

Thus, it is apparent, that the track relay is not only prevented from being picked up during the spanning of the detector track section, by a car, but also in the event that there is any loss of shunt by a particular car occupying the detector track section, while it is being detected by the utrasonic detector 30, the track relay T is prevented from being energized. This not only provides a fail-safe detection means for long cars, which span the detector track section, but also increases thereliability of the track section when the switch is traversed by short cars.

The embodiment of the invention illustrated in FIG. 5 may be used if it is desired to check the operation of the ultrasonic detecting apparatus during the passage of each car. In this embodiment, the winding of the track relay T is connected across the rails 12 and 13 of the detector track section at 58 and 59, through its own front contact 60. The power to the switch control circuitry 50 is controlled through a front contact 62 of the track relay T, a back contact 64 of a slow dropaway checking relay X, and a front contact 66, of the detector relay D. With this form of the invention, the

transducing apparatus must operate the detector relay D properly to its deenergized position, and the detector relay D must subsequently become reenergized before the switch machine can again be operated after a car has passed over the switch 10. When a car first shunts the rails 12 and 13 of the detector track section, the relay T is deenergized to open its front contact 60. This also opens the front contact 62 to remove energy from the switch control circuitry. When the car reaches the ultrasonic detecting head 30 above the casing 36, the relay D is deenergized which opens its front contact 66 to further insure that no power can be applied to the switch machine SM. The dropping away of the relay D with the track relay T also dropped away energizes the checking relay X by a circuit which extends from and includes back contact 68 of the relay D, the winding of the relay X and back contact 70 of the relay T, to The picking up of the relay X closes a stick circuit which extends from and includes front contact 72 and the winding of the relay X and the back contact 70 of the relay T, to This stick circuit prevents the dropping away of the relay X when a car has covered the detector head casing 36. The relay X is stuck up depending upon the track relay T to maintain a front contact 74 of the relay X closed so that the track relay T can again be reenergized when a car has traversed the track switch. The relay X is slow dropaway so that the front contacts of the track relay T will close before the relay X drops-away. In this embodiment, the track relay may pick up momentarily during the spanning of the detector track section, but the switch machine is prevented from operating by the open condition of back contact 64 of relay X and front contact 66 of relay D.

Thus, the concurrent shunting of the track circuit together with the deenergizing of the detector relay D permits the reestablishment of the track relay T after a car has traversed the switch. When a car ceases to influence the ultrasonic detecting apparatus, the relay X is held up solely through its previously described stick circuit, and when the car has left both the detector track section and the area of effectiveness of the ultrasonic detector the track circuit is restored to normal. If the checking relay X should inadvertently stay in its energized position, the switch machine cannot be operated because of the open back contact 64. If the relay X should fail to pick up, or the relay D should fail to drop away the track relay T cannot thereafter be picked up.

In the embodiment of the invention illustrated in FIG. 6, the track relay T is connected across the track rails 12 and 13 at 71 and 73. This energizing circuit not only includes a front contact 76 of the relay T and front contact 77 of the relay X connected in parallel with the front contact 76, but also a front contact 78 of the relay D. The relay D is provided with a back contact 80 for energizing the checking relay X independent of the condition of the track relay T, with a back contact 82 of the relay T providing a stick circuit through front contact 84 of the relay X. In this embodiment, when a car first shunts the detector track section, the relay T drops away to open its front contact 86 to remove the power from the switch machine. When the car influences the ultrasonic detector apparatus as it passes over the casing 36, the relay D drops away to open its front contact 78 and close its back contact 80. The opening of the front contact 78 further prevents the track relay from being erroneously picked up because of improper shunting of the track circuit when the car is influencing the detecting apparatus. The closing of the back contact 80 energizes the checking relay X by an obvious circuit to close the front contact 77 of relay X to permit the track relay T to be reenergized by the track circuit after the car has passed the track switch and left the detector track section. When a car is spanning the track section, the relay T is prevented from being picked up by the opening condition of the front contact 78 of the relay D. After a car has passed the detection casing 36 but still occupies the detector track section, the relay X is held up by the track relay T through its previously described stick circuit. When the train ceases to influence the detector head 30, front contact 78 closes, and when the car vacates the detector track section the relay T again becomes energized in a well known manner. The relay X is assumed to be held up long enough so that the relay T will pick up before the relay X drops away to reestablish the track circuit when a car vacates the detector track section.

If the ultrasonic detecting apparatus failed to function or relay X did not pick up, the track relay T could not pick up when a car spanned the track section because the relay X would not be energized to close the contact 77. If the ultnansonic detector relay D became deenergized, but failed to become reenergized after the passage of a car, the track relay T could not pick up because of the open contact 78.

Thus, in this embodiment it is apparent that the track relay T cannot become energized when a car is spanning the detector track section and also, the track relay cannot be reestablished unless the detector relay D drops away and then again picks up each time a car traverses the switch.

Thus, in the illustrated embodiments of the invention it is apparent that a car will be reliably detected traversing a track switch in a classification yard without the necessity of increasing the length of the detector track circuit to accommodate long cars, thereby maintaining the present efficiency and maximum use of the yards as presently constituted. It is also apparent, that with the benefit of the present invention the detector track sections may be shorter than presently constituted with their maximum length and location of the insulated joints in advance of the switch points being determined only by the rapidity of operation of the track switch,

Although, the present invention has been illustrated to employ a direct current closed track circuit, it is contemplated that an alternating track circuit could be utilized for controlling the operation of the track relay.

Having thus described several embodiments of the present invention, it is understood that these forms are selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it may assume. Also, it is to be further understood that various modifications, adaptations, and alterations may be applied to the specific form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention.

What we claim is:

1. A system for detecting the presence of a railway car traversing a track switch in a classification yard wherein said track switch is included in an electrically isolated detector track section and is operated to its opposite positions by a power switch machine, said system comprising detecting means positioned to be effective intermediate the ends of said track section to detect a car traversing the track switch, a detector relay operatively connected to said detecting means effective to be operated to one position when a car is being detected and operated to its other position when the track switch is vacant of a car, a track relay, a checking relay, a normally closed track circuit means including a source of energy connected across the rails of said track section and the winding and a front contact of said track relay and a contact of said detector relay in its one position to cause said track relay to remain energized when said track section is vacant of a car, circuit means including said checking relay effective to energize said checking relay to shunt said front contact of the track relay when said detector relay is in its other position, stick circuit means including a front contact of the checking relay effective to hold said checking relay energized when said track relay is deenergized and said detector relay is in its other position, and circuit means including a front contact of said track relay etfective to render said switch machine operative, whereby the operation of the detector relay from one position to the other by a car traversing the track switch is required to energize said track relay upon the vacating of the track section and track switch by a railway car.

2. A system as claimed in claim 1 wherein said checking relay stick circuit is opened only upon the vacating of said track section by a railway car when the detector relay is in its other position.

References Cited in the file of this patent UNITED STATES PATENTS McDonald Mar. 7, 1882 Livingston Jan. 5, 1932 Allen May 7, 1935 Dodd Dec. 15, 1936 Talbert June 1, 1948 Walsh Apr, 25, 1961 Hammond Mar. 6, 1962 Polster Apr. 17, 1962 

1. A SYSTEM FOR DETECTING THE PRESENCE OF A RAILWAY CAR TRAVERSING A TRACK SWITCH IN A CLASSIFICATION YARD WHEREIN SAID TRACK SWITCH IS INCLUDED IN AN ELECTRICALLY ISOLATED DETECTOR TRACK SECTION AND IS OPERATED TO ITS OPPOSITE POSITIONS BY A POWER SWITCH MACHINE, SAID SYSTEM COMPRISING DETECTING MEANS POSITIONED TO BE EFFECTIVE INTERMEDIATE THE ENDS OF SAID TRACK SECTION TO DETECT A CAR TRAVERSING THE TRACK SWITCH, A DETECTOR RELAY OPERATIVELY CONNECTED TO SAID DETECTING MEANS EFFECTIVE TO BE OPERATED TO ONE POSITION WHEN A CAR IS BEING DETECTED AND OPERATED TO ITS OTHER POSITION WHEN THE TRACK SWITCH IS VACANT OF A CAR, A TRACK RELAY, A CHECKING RELAY, A NORMALLY CLOSED TRACK CIRCUIT MEANS INCLUDING A SOURCE OF ENERGY CONNECTED ACROSS THE RAILS OF SAID TRACK SECTION AND THE WINDING AND A FRONT CONTACT OF SAID TRACK RELAY AND A CONTACT OF SAID DETECTOR RELAY IN ITS ONE POSITION TO CAUSE SAID TRACK RELAY TO REMAIN ENERGIZED WHEN SAID TRACK SECTION IS VACANT OF A CAR, CIRCUIT MEANS INCLUDING SAID CHECKING RELAY EFFECTIVE TO ENERGIZE SAID CHECKING RELAY TO SHUNT SAID FRONT CONTACT OF THE TRACK RELAY WHEN SAID DETECTOR RELAY IS IN ITS OTHER POSITION, STICK CIRCUIT MEANS INCLUDING A FRONT CONTACT OF THE CHECKING RELAY EFFECTIVE TO HOLD SAID CHECKING RELAY ENERGIZED WHEN SAID TRACK RELAY IS DEENERGIZED AND SAID DETECTOR RELAY IS IN ITS OTHER POSITION, AND CIRCUIT MEANS INCLUDING A FRONT CONTACT OF SAID TRACK RELAY EFFECTIVE TO RENDER SAID SWITCH MACHINE OPERATIVE, WHEREBY THE OPERATION OF THE DETECTOR RELAY FROM ONE POSITION TO THE OTHER BY A CAR TRAVERSING THE TRACK SWITCH IS REQUIRED TO ENERGIZE SAID TRACK RELAY UPON THE VACATING OF THE TRACK SECTION AND TRACK SWITCH BY A RAILWAY CAR. 